Olson, K., Lepkowski, J. M., & Garabrant, D. H. (2011). An Experimental Examination of the Content of Persuasion Letters on Nonresponse Rates and Survey Estimates in a Nonresponse Follow-Up Study. Survey Research Methods, 5(1), 21–26. https://doi.org/10.18148/srm/2011.v5i1.4324